SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '979c9e586f146ea4bb2d7d0a391c55ee61b58d684fdacf0a102373ab808b6c58' 
  AND token = 'IEHjaDYJOlHMlJWrURlP3sKkQonIgRGhg9QrJdVWs5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}